Method of uniting sheets of brass, aluminium, and other metals or alloys of high conductivity for heat.



N. PROSTLER.

METHOD OI UNITING SHEETS 0F BRASS ALUMINIUM, AND OTHER METALS 0R ALLOYS OF HIGH OONDUGTIVITY FOB HEAT. 21.10am: rmzn SEPT.19 1914,

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Patented Mar. 30, 1 915.

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mam ma am imam: 11, ma gain No. 730,731. Divided and this application filed September To all whom it ma concern: Be it known t at I, Nommn'r Pnos'rmm, engineer, a subject of King of Bavana, re-

siding at Berlin, in the Empire of Germany,

have invented a certain new, useful, and

. Improved Method of Uniting Sheets of Brass, Aluminium, and other Metals or Alloys of Hi h Conductivity for Heat, of which the f0 lowing is a specificat1on,ref erenceibeing had therein to the accompanying drawing.

My, invention relates to a method of uniting abutting sheets ofbrass, German silver, aluminium and other metals or alloys of high conductivity for heat, that is of a higher heat conductivity than iron. Now, brass being a typical representatlve of materials of the above mentioned class, I wish it to be well understoodthat, when in the following specification and in the claims I shall s eak of brass for more simplicity, all other a loys or metals having the same properties i as to conductivity for heat will he meant as equivalents for brass.

The present application is a division from a (to-pending application filed Nov. 11, 1912, Serial No. 730,737 for an improved method ofuniting sheets of brass, aluv minium and other metals or alloys ofhigh in one single piece of metal.

Asfar as applicant'is aware, all former attempts to unite abutting sheets of brass by electric heating with or without inserting a soldering strip between the meeting edges of the sheets remained without success. Now,

as it has been proved by thorough experiments, the problem of welding together abutting sheets of brass, German. silver, alumlnium and other metals or alloys of a high conductivity for heat is completely trade-roller solved by the method or process forming the object of the present invention.

This method or process of uniting or fastening together twosheets of brass and the like consists in abuttingv togetherthe lateral edges of said two sheets, exerting perpendlcularly to the outer flat surface or planeof said sheets a pressure at the place where said sheets meet together, and in the direction of pressure passing an electric current sufiiclent to fuse or melt together the abutting edges of said sheets. The current must be of suflicient amount and the pressure adequate as the efiect is essentially due to the current used in combination with the pressure applied, so that the metal ismelted at the place of welding and the abutting edges fused together, while some. melted metal is also forced by the pressing action, between the abutting metallic edges so as to make the joint or seam more perfect. As a matter of fact the -contacting pieces of metal in the present rocess are melted or fused together rather t an welded according to the real meaning of this Word. Consequently, the

present new process may be more properly termed a process of fusing or melting together metals. than a welding process proper.

Practically I use according to 'my. process a pressure much smaller than the pressure usual for welding iron, and a stronger current is needed than in welding iron. The process or method may he performed with the help of the usual point or, spot welding electrodes or by using "electrode-rollers by,

which thepressure on the sheets is applied transversely to the direction of the abutting.

ed es of the sheets. i y I n the accompanying'drawing forming a part of this specification Fi ure 1 represents the uniting of two sheets 0 brass orequivalent material withabutting lateral edges by means of point electrodes. Fig. 2 illustrates the uniting of two sheets of brass or equivalent material abutting with their lateral edges by means of two electrode-rollers. Fig. 3 shows the uniting of two sheets of brass or equivalent material with abutting lateral edges by means ofan upper elecand a lower rod-shaped e1ec- In Fig.1 a, I) are the abutting sheetsof brassor equivalent material; a, (3 point or spot welding electrodes of usual construction, each point electrode contacting partly with the edge of the sheet a and partly with a, 6, while causing the electric current to pass acrosssaid parts which meet or abut together.

It will be easily understood that the transverse application of pressure referred to may be obtained in a manner familiar to the person skilled in the art either by shifting the work-pieces'relatively to the electroderollers or by correspondingly moving the. electrode-rollers upon the surface of the g metal sheets.

In carrying out this process the electrode pressure should not exceed kilograms (about 66 lbs.),while for the uniting of sheets of 0.5 mm. thickness an electrode pressure of 1015 kilograms (about 22-33 lbs.) is preferable, it being 'ofcourse understood that the actual electrode pressure is to be governed by the thickness of the sheets to be united. I

In Fig. 3 the mode of operation and elfect is the same as in Fig.2 with the only differonce that an upper electrode-rollers and a lower rod-shaped electrode 9 are provided for performing the fusing process. I

For a proper understanding of this present method it must be clearly appreciated thatthe action of brass and similar metals or alloys under high temperatures is quite different from the action of steel and iron, in that the latter assume a plastic condition before becomingliquid under the influence of high temperatures. In the welding of.

steel and iron by what is known as the spot welding process, the resistance of the steel or iron to the passage of the electric current therethrough generates suflicient heat in the steel or. iron to bring them to a plastic'condi tion, at which time the pressure from the electrodes welds or unites the plates. In the case of brass and similar metals or alloys however, there is no intermediate or plastic stage of the metal before it-reaches a liquid condition, and brass is similar in this respect to lead, in that it iseither solid or liquid, and when solid is turned into a liquid condition under the influence of high temperature without first passing through a plates themselves causes a locahzed liqueplastic condition, as is acharacteristic of teamed,"

between the electrodes.

steel and iron. With aproper understanding of this fundamental difference between theaction of steel and iron on the one hand and brass andsimilar metals or alloys on] the other, it will be understood that the same rocess which. can besuccessfully employe for the welding of sheets of steel and iron electrically, as by the spot welding process, can not be employed for the uniting of brass and similar metals or alloys electrically and that the diflerence in the method employed for the uniting of thin sheets of brass and similar metals or alloys is not a difference of degree, but is'essentially' a difference of kind or character of the method orprocess itself, as willbe clearly understood from the" following.

In the uniting of thin sheets of brass and similar metals or alloys it is essentialthat the adjacent faces of the sheets in contact with the electrodes be raised to a sufficiently high temperatureto become liquid and melt together to produce a joining or union of the plates, and it is equally essential that the body, or more' properly, the interior portion of the plates just adjacent the abutting edges thereof be not raised to asufliciently high temperature to becomeliquefied, for if such a liquefied conditionexists in the interior of the plates between the electrodes, any appreciable pressure of the electrodes on the plates would instantly displace the liquid metal betweenthe electrodes and result in a hole'or aperture through theplates instead of a uniting or joining of the same. It must be therefore understood that in order to effect the joining or uniting of thin sheets of brass or the like thetemperature of the surface contacting with the electrodes must be raised to a temperature exceeding that of the temperature of the interior of the plates Such a condition is brought about by this present process, in that the application of a relatively light pressure of the electrodes on the plates causes what might be termed a slight con-. tact or what is technically called a poor contact between the electrodes and the plates. This slight contact offers a greater resistance to the passage of the current at the points of contact and localizes the heat generatedby said greater resistance at these contacting surfaces of the plates with the electrodes, while the body or. interior of the plates ofi'ers less resistance to the passage of the current and consequently the said body or interior of the plates is not raised to the same high temperature as. the lightly contacting surfaces. The efl'ect therefore on the plates upon application of a relatively light pressure is that the heat generated by the resistance to the passage of the current at these contacting surfaces being greaterthan the heat generated in the interior of the 85 plates at less than a melting temperature.

faction of the plates at these contacting surfaces without causing a liquefaction of the metal in the interior of the plates, and adjacent to the contacting surfaces thereof between the electrodes. The effect of this is that the plates are melted rather than welded together, which melting is localized at the contactin surfaces of the plates and the electrodes. its a consequence of this a high pressure of the electrodes on brass plates or the like results in no weld or melting of the metal, as whenever the contact between the While on the other hand'if the current be of such character to cause a melting of the metal under an intimate contact and high pressure of the electrodes, said melting occurs not only at thecontacting surfaces of the plates and the electrodes, but in the interior of the platesthemselves between the electrodes. The pressure of the electrodes instantly displaces the fluid metal and produces a hole in the plates instead of a union or joining of thesame.

From the foregoing it will be seen that the purpose of this present method is really to maintain the lates of brass or like metal or alloy at a su ciently light contact with the electrodes to produce a melting temperature at the contacting surfaces only and at the same time maintain the interior of the As distinguishing this method from the method of welding steel and iron electrically itwill be understood that it is by no means essential in the Welding of steel and iron to treat the same so that the contacting surfaces thereof are at a higher temperature than the interior of the plates between the electrodes, as the heat generated in steel or iron plates is due entirely to the resistance to the passage of current through the steel or iron plates themselves and not to the resistance to the passage of the current at the actual contacting surfaces of the steel and iron plates with the electrodes.

I claim:

1. The hereinbefore described process of uniting together thin sheets of metals of a higher conductivity for heat than iron, such as brass and like metals or alloys, consist ing in abutting together said metallic sheets, exerting perpendicularly to the abutting edges of said sheets an' electrode pressure suflicient to produce a slight contact between the plates and the electrodes, and in passing through-the plates an electrical current to melt the adjacent contacting surfaces of the sheets.

2. The hereinbefore described process of uniting together thin sheets of metal of a higher conductivity for heat than iron, such as-brass and like metals or alloys, consisting in bringing together said metallic sheets by abutting their edges, exerting perpendicularly to the abutting edges of said sheets an electrode pressure suflicient to cause a relatively slight contact between the surfaces of the sheetsand the electrodes'to provide an increased resistance to the passage of an electrical current between the electrodes and the surfaces of the sheets, and effecting the uniting of the sheets by melting the same at their abutting edges by passing an electric current through the sheets.

3. The hereinbefore described process of uniting together thin-sheets of metal of a higher conductivity for heat than iron, such as brass and like metals or alloys, consisting 'in bringing together said metallic sheets by abutting their edges, exerting transversely by abutting their edges, exerting transversely to the abutting ed es of said sheets an electrode pressure su cient to cause a relatively slight contact between the surfaces of the sheets and the electrodes to provide an increased resistance to the passage of an electrical current between the electrodes and the sheets, and effecting the uniting of the sheets by melting the same at -their abutting edges by passing an electric current through the sheets.

5. The herein described process-of uniting together thin sheets of brass and like metals or alloys consisting in bringing said sheetstogether by abutting'their edges between two electrodes and applying to the said sheets at the electrodes a pressure sufficientto cause a relativelyslight contact between the sheets and the electrodes to provide an increased resistance to the passage of an electrical current at the contacting surfaces of the plates with the electrodes, and in passing an electrical current from one electrode to the other through the plates to cause a localized melting of the metal at the con tacting surfaces of the plates with the electrodes which is the point of increase of electrical resistance to melt the abutting edges of the sheets together. I

6. The herein described process of unit-- ing together thin sheets of brass and like metals or alloys consisting in abutting together said sheets between two electrodes and in contact therewith, and in maintain- 7. The herein described process of uniting together thin sheets of brass or like metals or alloys consisting in abutting together said sheets between two electrodes and ,con-

tact therewith, and in applying to the said sheets at the point of contact of the electrodes with thesaid sheets a slight pressure so as to produce a relatively slight contact between the said sheets and the electrodes,

and in passing an electrical current through the said sheets from one electrode to the other to produce a localized melting of the sheets at their point of contact with the said electrodes.

In testimony whereof I aflix my signature in presence of two witnesses.

' N ORB'ERT PROSTLER. Witnesses:

HENRY HASPER,

' WOLDEMAR HAUPT. 

